<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Flex Margin</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }
        .container {
            display: flex;
            width: 100vw;
            height: 100vh;
        }
        .box {
            width: 30px;
            height: 500px;
            margin: auto;
            background: pink;
        }
    </style>
</head>
<body>
    <div class="container">
        <div class="box">1</div>
        <div class="box">1</div>
        <div class="box">1</div>
        <div class="box">1</div>
        <div class="box">1</div>
        <div class="box">1</div>
    </div>
</body>
</html>